#解密
def Dec(C,k):
    kls=ExpandKey(k)
    als=list()
    bls=list()
    cls=list()
    dls=list()
    als.append(C[0:32])
    bls.append(C[32:64])
    cls.append(C[64:96])
    dls.append(C[96:128])
    als.append(xor32(als[0],cls[0]))
    bls.append(xor32(F(als[1],kls[94]),bls[0]))
    dls.append(xor32(bls[0],dls[0]))
    cls.append(xor32(F(dls[1],kls[95]),cls[0]))
    for i in range(1,48):
        als.append(xor32(bls[i],dls[i]))
        bls.append(xor32(F(als[i+1],kls[2*(48-i)-2]),als[i]))
        dls.append(xor32(als[i],cls[i]))
        cls.append(xor32(F(dls[i+1],kls[2*(48-i)-1]),dls[i]))
    P=als[48]+bls[48]+cls[48]+dls[48]
    return P
